ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-10-29773-2010 A reanalysis of MODIS fine mode fraction over ocean using OMI and daily GOCART simulations Jones T. A. 1 3 Christopher S. A. 1 2 Earth System Science Center, UAHuntsville, Huntsville, AL, USA Department of Atmospheric Sciences, UAHuntsville, Huntsville, AL, USA Cooperative Institute for Mesoscale Meteorological Studies, Norman, OK, USA 07 12 2010 10 12 29773 29807 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/10/29773/2010/acpd-10-29773-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/10/29773/2010/acpd-10-29773-2010.pdf

Using daily Goddard Chemistry Aerosol Radiation and Transport (GOCART) model simulations and columnar retrievals of 0.55 μm aerosol optical thickness (AOT) and fine mode fraction (FMF) from the Moderate Resolution Imaging Spectroradiometer (MODIS), we estimate the aerosol concentration and particle size over the global oceans between June 2006 and May 2007 due to black carbon (BC), organic carbon (OC), dust (DU), sea-salt (SS), and sulfate (SU) components. Using Aqua-MODIS aerosol properties embedded in the CERES-SSF product, we find that the mean MODIS FMF values are SS: 0.31&plusmn;0.09, DU: 0.49&plusmn;0.13, SU: 0.77&plusmn;0.16, and (BC+OC):0.80&plusmn;0.16. We further combine information from the ultraviolet spectrum using the Ozone Monitoring Instrument (OMI) onboard the Aura satellite to improve the classification process, since dust and carbonaceous aerosols have positive Aerosol Index (AI) values >0.5 while other aerosol types have near zero values. By combining MODIS and OMI datasets, we were able to identify and remove data in the SU and CC regions that were not associated with those aerosol types. <br><br> The same methods used to estimate aerosol size characteristics from MODIS data within the CERES-SSF product were also applied to Level 2 (L2) MODIS aerosol data from both Terra and Aqua satellites for the same time period. As expected, FMF estimates from L2 Aqua data agreed well with the CERES-SSF dataset, also from Aqua. However, the FMF estimate for DU from Terra data was significantly lower (0.37 vs. 0.49) indicating that sensor calibration, sampling differences and/or diurnal changes in DU aerosol size characteristics were occurring. Differences for other aerosol types were generally smaller. Sensitivity studies show that a difference of 0.1 in the estimate of the anthropogenic component of FMF produces a corresponding change of 0.2 in the anthropogenic component of AOT (assuming a unit value of AOT). This uncertainty would then be passed along to any satellite-derived estimates of anthropogenic aerosol radiative effects.

 References Bellouin,~N., Boucher,~O., Haywood,~J., and Reddy,~M S.: Global estimate of aerosol direct radiative forcing from satellite measurements, Nature, 438, 1138–1141, \doi10.1038/\breaknature04348, 2005. Bellouin,~N., Jones,~A., Haywood,~J., and Christopher,~S A.: Updated estimate of aerosol direct radiative forcing from satellite observations and comparison against the Hadley Centre climate model, J Geophys. Res., 113, D10205, \doi10.1029/2007JD009385, 2008. Chin, M., Ginoux, P., Kinne, S., Torres, O., Holben, B., Duncan, B., Martin, R., Logan, J., Higurashi, A., and Nakajima, T.: Aerosol distributions and radiative properties simulated in the GOCART model and comparisons with observations, J Atmos. Sci., 59, 461–483, 2002. Chin, M., Ginoux, P., Lucchesi, R., Huebert B., Weber, R., Anderson, T., Masonis, S., Blomquist, B., Bandy, A., and Thornton, D.: A~global aerosol model forecast for the ACE-Asia field experiment, J Geophys. Res., 108(D23), 8654, \doi10.1029/2003JD003642, 2003. Chin, M., Chu, D., Levy, R., Remer, L., Kaufman, Y., Hoblen, B., Eck, T., and Ginoux, P.: Aerosol distribution in the Northern Hemisphere during ACE-Asia: results from global model, satellite observations, and Sun photometer measurements, J Geophys. Res., 109, D23S90, \doi10.1029/2004JD004829, 2004. Chin,~M., Diehl,~T., Ginoux,~P., and Malm,~W.: Intercontinental transport of pollution and dust aerosols: implications for regional air quality, Atmos. Chem. Phys., 7, 5501–5517, \doi10.5194/acp-7-5501-2007, 2007. Chin, M., Diehl, T., Dubovik, O., Eck, T. F., Holben, B. N., Sinyuk, A., and Streets, D. G.: Light absorption by pollution, dust, and biomass burning aerosols: a global model study and evaluation with AERONET measurements, Ann. Geophys., 27, 3439–3464, doi:10.5194/angeo-27-3439-2009, 2009. Christopher,~S A. and Jones,~T A.: Satellite-based assessment of cloud-free net radiative effect of dust aerosols over the Atlantic Ocean, Geophys. Res. Lett., 34, L02810, \doi10.1029/\break2006GL027783, 2007. Christopher,~S A. and Jones,~T A.: Short-wave aerosol radiative efficiency over the global oceans derived from satellite data, Tellus, 60B, 636–640, doi:080529042315537, 2008a. Christopher,~S A. and Jones,~T A.: Sample bias estimation for cloud-free aerosol effects over global oceans, IEEE~T. Geosci. Remote, 46(6), 1728–1732, 2008b. Christopher,~S A., Zhang,~J., Kaufman,~Y J., and Remer,~L A.: Satellite-based assessment of top of atmosphere anthropogenic aerosol radiative forcing over cloud-free oceans, Geophys. Res. Lett., 33, L15816, \doi10.1029/2005GL025535, 2005. Christopher,~S A., Johnson,~B., Jones,~T A., and Haywood,~J.: Vertical and spatial distribution of dust from aircraft and satellite measurements during the GERBILS field campaign, Geophys. Res. Lett., 36, L06806, \doi10.1029/2008GL037033, 2009. Dubovik,~O., Holben,~B N., Eck,~T F., Smirnov,~A., Kaufman,~Y J., King,~M D., Tanré,~D., and Slutsker,~I.: Variability of absorption and optical properties of key aerosol types observed in worldwide locations, J Atmos. Sci., 59, 590–608, 2002. Ginoux,~P. and Torres,~O.: Empirical TOMS index for dust aerosol: applications to model validation and source characterization, J Geophys. Res., 108(D17), 4534, \doi10.1029/\break2003JD003470, 2003. Gupta,~P. and Christopher,~S A.: Seven year particulate matter air quality assessment from surface and satellite measurements, Atmos. Chem. Phys., 8, 3311–3324, \doi10.5194/acp-8-3311-2008, 2008. Hsu,~N C., Herman,~J R., Gleason,~J F., Torres,~O., and Seftor,~C J.: Comparisons of the TOMS aerosol index with Sun-photometer aerosol optical thickness: results and applications, J Geophys. Res., 104(D6), 6269–6280, \doi10.1029/1998JD200086, 1999. Jones,~T A. and Christopher,~S A.: MODIS derived fine mode fraction characteristics of marine, dust, and anthropogenic aerosols over the ocean, constrained by GOCART, MOPITT, and TOMS, J Geophys. Res., 112, D22204, \doi10.1029/2007JD00897, 2007a. Jones,~T A. and Christopher,~S A.: Statistical variability of top of atmosphere cloud-free shortwave aerosol radiative effect, Atmos. Chem. Phys., 7, 2937–2948, \doi10.5194/acp-7-2937-2007, 2007b. Jones,~T A., Christopher,~S A., and Quaas,~J.: A~six year satellite-based assessment of the regional variations in aerosol indirect effects, Atmos. Chem. Phys., 9, 4091–4114, \doi10.5194/acp-9-4091-2009, 2009. Kaufman,~Y J., Boucher,~O., Tanré,~D., Chin,~M., Remer,~L A., and Takemura,~T.: Aerosol anthropogenic component estimated from satellite data, Geophys. Res. Lett., 32, L17804, \doi10.1029/2005GL023125, 2005a. Kaufman,~Y J., Koren,~I., Remer,~L A., Tanré,~D., Ginoux,~P., and Fan,~S.: Dust transport and deposition observed from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS) spacecraft over the Atlantic Ocean, J Geophys. Res., D10S12, \doi10.1029/2003JD004436, 2005b. Kleidman,~R., O'Neill,~N., Remer,~L., Kaufman,~Y., Eck,~T., Tanré,~D., Dubovik,~O., and Holben,~B.: Comparison of Moderate Resolution Imaging Spectroradiometer (MODIS) and Aerosol Robotic Network (AERONET) remote-sensing retrievals of aerosol fine mode fraction over ocean, J Geophys. Res., 110, D22205, \doi10.1029/2005JD005760, 2005. Levin,~Z., Ganor,~E., and Gladstein,~V.: The effects of desert particles coated with sulfate on rain formation in the Eastern Mediterranean, J Appl. Meteorol., 35, 1511–1523, 1996. Loeb,~N G. and Manalo-Smith,~N.: Top-of-atmosphere direct radiative effect of aerosols over global oceans from merged CERES and MODIS observations, J Climate, 18, 3506–3526, 2005. Remer,~L A., Kaufman,~Y J., Tanré,~D., Mattoo,~S., Chu,~D A., Martins,~J V., Li,~R.-R., Ichoku,~C., Levy,~R C., Kleidman,~R G., Eck,~T F., and Vermote,~E.: The MODIS aerosol algorithm, products and validation, J Atmos. Sci., 62, 947–973, 2005. Remer, L. A., Kleidman, R. G., Levy, R. C., Kaufman, Y., Tanré, D., Mattoo, S., Martins, J., Ichoku, C., Koren, I., Yu, H., and Holben, B.: Global aerosol climatology from the MODIS satellite sensors, J Geophys. Res., 113, D14S07, \doi10.1029/2007JD009661, 2008. Seland,~O., Iversen,~T., Kirkevag,~A., and Storelvmo,~T.: On basic shortcomings of aerosol-climate interactions in atmospheric GCMs, Tellus, 60A, 459–491, \doi10.1111/j.1600-0870.2008.00318.x, 2008. Smirnov,~A., Holben,~B N., Eck,~T F., Slutsker,~I., Chatenet,~B., and Pinker,~R T.: Diurnal variability of aerosol optical depth observed at AERONET (Aerosol Robotic Network) sites, Geophys. Res. Lett., 29, 2115, \doi10.1029/2002GL016305, 2002. Textor,~C., Schulz,~M., Guibert,~S., Kinne,~S., Balkanski,~Y., Bauer,~S., Berntsen,~T., Berglen,~T., Boucher,~O., Chin,~M., Dentener,~F., Diehl,~T., Easter,~R., Feichter,~H., Fillmore,~D., Ghan,~S., Ginoux,~P., Gong,~S., Grini,~A., Hendricks,~J., Horowitz,~L., Huang,~P., Isaksen,~I., Iversen,~I., Kloster,~S., Koch,~D., Kirkevåg,~A., Kristjansson,~J E., Krol,~M., Lauer,~A., Lamarque,~J F., Liu,~X., Montanaro,~V., Myhre,~G., Penner,~J., Pitari,~G., Reddy,~S., Seland, Ø., Stier,~P., Takemura,~T., and Tie,~X.: Analysis and quantification of the diversities of aerosol life cycles within AeroCom, Atmos. Chem. Phys., 6, 1777–1813, \doi10.5194/acp-6-1777-2006, 2006. Torres,~O., Bhartia,~P K., Herman,~J R., Ahmad,~Z., and Gleason,~K.: Derivation of aerosol properties from satellite measurements of backscattered ultraviolet radiation: theoretical basis, J Geophys. Res., 103, 17099–17110, 1998. Torres,~O., Bhartia,~P K., Herman,~J R., Sinyuk,~A., Ginoux,~P., and Holben,~B N.: A~long-term record of aerosol optical depth from TOMS observations and comparison to AERONET measurements, J Atmos. Sci., 59(3), 398–413, 2002. Torres,~O., Tansksnen,~A., Veihelmann,~B., Ahn,~C., Braak,~R., Bhartia,~P K., Veefkind,~P., and Levelt,~P.: Aerosols and surface UV products from Ozone Monitoring Instrument observations: an overview, J Geophys. Res., 112, D24S47, \doi10.1029/2007JD008809, 2007. Wang,~J., Xia,~X., Wang,~P., and Christopher,~S A.: Diurnal variability of dust aerosol optical thickness and Angstrom exponent over dust source regions in China, Geophys. Res. Lett., 31, L08107, \doi10.1029/2004GL019580, 2004. Weaver, C., Da-Silva, A., Chin, M., Ginoux, P., Dubovik, O., Flittner, D., Zia, A., Remer, L., Holben, B., and Watson, G.: Direct insertion of MODIS radiances in a~global aerosol transport model, J Atmos. Sci., 64, 808–826, 2007. Yu,~H., Kaufman,~Y J., Chin,~M., Feingold,~G., Remer,~L A., Anderson,~T L., Balkanski,~Y., Bellouin,~N., Boucher,~O., Christopher,~S., DeCola,~P., Kahn,~R., Koch,~D., Loeb,~N., Reddy,~M S., Schulz,~M., Takemura,~T., and Zhou,~M.: A~review of measurement-based assessments of the aerosol direct radiative effect and forcing, Atmos. Chem. Phys., 6, 613–666, \doi10.5194/acp-6-613-2006, 2006. Yu, H., Chin, M., Remer, L. A., Kleidman, R., Bellouin, N., Blan, H., and Diehl, T.: Variability of marine aerosol fine-mode fraction estimates of anthropogenic aerosol component over cloud-free oceans from the Moderate Resolution Imaging Spectroradiometer (MODIS), J Geophys. Res., 114, D10206, \doi10.1029/2008JD010648, 2009. Zhang,~J., Christopher,~S A., Remer,~L A., and Kaufman,~Y J.: Shortwave aerosol cloud-free radiative forcing from Terra, I:~angular models for aerosols, J Geophys. Res., D10(S23), D10S23, \doi10.1029/2004jd005008, 2005. Zhang,~J. and Reid,~J S.: MODIS aerosol product analysis for data assimilation: assessment of over-ocean level 2 aerosol optical thickness retrievals, J Geophys. Res., 111, D22207, \doi10.1029/2005JD006898, 2006.